An Arizona lawman who refused for more than a year to hand over records to an investigation into allegations that his department discriminated against Hispanics was sued by the US Justice Department yesterday.

The lawsuit called the defiance of Sheriff Joe Arpaio and his office "unprecedented". It said the federal government had been trying since March 2009 to get officials to comply with its inquiry into alleged discrimination, unconstitutional searches and seizures, and jail policies that discriminate against people with limited English skills.

Mr Arpaio, 78, the elected sheriff of Maricopa County, had been given until 17 August to hand over papers that the federal government asked for 15 months ago. Yesterday, he called the Justice Department's action "harassment". His office has said it will not hand over additional documents because federal officials have not said exactly what they are investigating.

"They have hundreds of thousands of reports, hundreds of thousands," Mr Arpaio added. "They're so broad, we're trying to narrow it down. We're trying to work with them."

The suit is the latest action against Arizona by the federal government. Earlier, it sued the state to stop its strict new law that requires police to question people about their immigration status if officers suspect they are in the country illegally.